Functional circuit blocks that were previously manufactured as individual integrated circuit devices (ICs) presently can be implemented within a single IC. Functional circuit blocks within an IC often intercommunicate, exchanging information, either uni-directionally or bi-directionally, or communicate with external electrical systems. For example, a flash memory block can store and provide data describing an initial setup to another circuit block, such as a microprocessor core, within a same IC.
Each circuit block can be powered by a unique power supply. Each power supply can provide a unique voltage potential. Each circuit block may contain a different circuit architecture or share a same circuit architecture, but be implemented with differing device types and/or device sizes, as compared to each other circuit block. As a result of differing power supplies to, and differing circuits being implemented within, each circuit block within an IC, subsequent to powering on the IC, the time required for each circuit block to reach operability may differ. The differing time to operability, or “power-on time,” for each circuit block determines when the circuit block can effectively communicate, i.e., successfully transmit or receive data.
As each circuit block within an IC may have a unique power-on time, each circuit block can begin to effectively communicate at a different time subsequent to the moment that power is supplied to the IC. In that case, a first circuit block within an IC may attempt to communicate with a second circuit block within the IC prior to the second circuit block being capable of effective communication. The different power-on times of the various circuit blocks within the IC can result in miscommunication between circuit blocks at start-up. Inter-circuit block miscommunication is not limited to powering on an IC from an off state. Inter-circuit block miscommunication also can occur subsequent to an interruption of power to a circuit block within the IC or a reduction of the voltage potential provided to a circuit block below a minimum required functional voltage potential.